Coring apparatus



A ril 14, 1953 J. c. STOKES CORING APPARATUS 2 SHEETS-SHEET 1 Filed March 7, 1951 INVENTOR. J W

m E N R m T EM April 1953 J. c. STOKES 2,634,956

CORING APPARATUS Filed March 7, 1951 2 SHEETSSHEET 2 I I E I /8 (/0/7/7 C. J fakes INVENTOR.

Patented Apr. 14, 1953 r:

John '0. .Stokes, Houston, Tex assi gnor to Reed, holler .Bit Company. H ust n, a narrow:

tion o e s Application March 7, 1951, Serial N0..21-4,'357

1 V This invention relates to new and usefulimmovements in coring apparatus and relates particularly to coring apparatus of the removabletype.

As is well known, it is the general practice to employ a removable core barrel for cutting a core in advance of the drill bit with the particular advantage of the removable barrel being that the core may he cut and retrieved without removing the drill pipe and bit from the here. The removable-type core barrel ordinarily extends through an axial bore or openingin the drill bit when in operative position and in the past this bore or opening has been of a constant diameter which is substantially equal to the external diameter of the core barrel. It has been found that during the coring operation and while the core barrel is extending through the here oropeni-ng in the drill bit, mud, cuttings and other extraneous matter may enter the space between the exterior of the core barrel and the wall of the bore or opening in the drill bit and may become packed therein, with the result that the core 'barrelbecomes stuck within said bore or opening and is diflicult to remove.

It is, therefore, one object of this invention to provide an improved coring apparatus wherein sticking of the removable core barrel within the here or opening of the drillhit is obviated to assure that said core barrel may be readily removed when desired.

An important object is to provide the drill bit with an axial bore or opening having its lower portion of a diameter substantially equal to the external diameter of the core barrel and having I its upper portion enlarged outwardly toward the upper end thereof, whereby when the core barrel.

is extending therethrough said barrel is, in substa al n agem nt. with the l wer po tion of the wall of the bore but is out of contact with the remainder thereof; the enlargement of the upper portion of the bore facilitating removal of the core barrel even though foreign matter may have accumulated in the area between the barrel and the. Wall of the bore.

A further object is to provide the wall of the axial opening or here of a drill bit, through which a removable core barrel extends, with longitue dinal passages which are of such shape and dispo ition that emoval oitheoore barrel is read-11y accompli hed when :desired.

A still rur-thor object i o provi e in the brid support of, a drill bi axial tapered openin extend a thorethroushwith the enlarg d por tion of the. openin at the upper end of thesu s rt, the wall of theopening being :formed with longitudinal passa es whioh permit simulatio past a core barrel extending through the opening. whereby the possibility of said here barrel -.stio.k-- ins hin the opening in the event that foreign matter accumulates in the space between th barrel and wall of the opening obviated.

Still another object :is to provide an apparatus. of the character described, wherein-the. core barrel is properly supported when in core-taking position but yet is readily removable at any time without danger of sticking.

Theeonstruction designed to carryout the invention will be hereinafter described together with other features thereof.

The invention will :be more readily understood from a. reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an exampleof' the invention is shown, and wherein:

Figure 1 isa vertical sectional view of an appa ratus, constructed ina'accordance with the inven 'tion, Figure 2 is a vertical sectional view, taken on the line 2-5-12 of Figure '1,

Figure 3 is a sectional view of the bridge struc ture of the outer *bit, illustrating a tapered bore,

Figure. 4 is a sectional view, taken on the line 454 .of Figure 3, and

Fig. 5 is a cross-sectional view, taken on the line 5-43 of Figure 4.

- 1n the drawings, the numeral ll! designates an outer core bit which is attached in the usual manner to the usual drill string or 'pipe I I. The bit is illustrated as a roller type bit having a pair of diametrically opposed outside cutters l2 and a pairof diametrioally opposed inside cutters l3; The usual bridge I4 is disposed between the cutters and is formed with an axial bore 15 extending therethrough. The details of construction of the bit and the cutters is subject to variation.

- A core barrel l6 having -a-cutter head I1 is adapted to be inserted within the lower portion ofthe drillstring with the outter'head I! being adapted to be lowered in position to cut a core when desired. Ordinarily this core barrel is dropped into position and removed by means of a wire line, and it has been the practice in the past to form the axial opening IS in the bridge I4 of a constant diameter which is substantially equal to the external diameter of the core head II. It has been found that where the bore of the opening I5 is of a constant diameter, mud and cuttings tend to accumulate between the external surface of the cutter head I! and the wall of the opening I5 with the'resu'lt that removal of the core barrel and cutter, after the coring operation is complete, is difllcult.

In carrying out the present invention the opening I5 which extends through the bridge I4 has a relatively short section at its lower portion, indicated at20, formed of a constant diameter which is adapted to engage the external surface of the cutter head I]. Above the constant diameter section 20 the wall of the bore or opening I5 is tapered or enlarged outwardly toward the upper end'of the bridge, this tapered wall portion being indicated at 2|. When the core cutter head I! is extending through the opening I5 of the bridge the section- 20 at the lower portion 29 of said opening engages the external surface of the cutter head and functions as a guide and support for 7 said head. Above the section 20 an annular tapered space, indicated at A in Figures 1 and 2, is provided, said space being formed between the external surface of the cutter head I! and the inclined or tapered surface 2I of the bore of the bridge.

A plurality of longitudinally extending recesses or grooves 22 may be formed in the wall of the bore or opening I5 and these recesses establish communication between the tapered annular space A and the area below the cutter head. It is noted that the grooves or recesses permit circulation' past the core barrel extending through the opening but if desired, said'grooves may be omitted.

In the use ofthe apparatus it will be evident that when the core barrel I6 and its cutter head H are, positioned within the 'bit as shown in Figure 1, the cutter head is supported at its lower end by the lowersection 20 within the lower portion of the opening or bore 15, while the upper end of the cutter is supported by the bearing surface I8a of the collar I8 within the upper end of the bit. Extending upwardly from the lower bearing section 20 is the annular space A, the upper end of which is in communication with the area below the fluid passages I9 in the bit. Thus, during thecoring operation any mud or cuttings which might accumulate within the opening 'or'bore I5 between the outer surface of the cutter head I1 and the wall of the bore will be washed downwardly within the annular space A and if the grooves 22 are employed then through the said grooves into the area below the bridge. Thus, the construction is such that an accumulation of-mud, cuttingsor'otherextraneous matter in the area'between the outer surface of the cutter head I! and the wall of the bore I5 is prevented. Furthermore, if any cuttings or extraneous matter do accumulate within this space,

4 the tapering or enlarged upper end of the bore I5 will permit the cutter head to be easily removed upwardly from within the bore and without any binding or sticking of the cutter head within said head. The arrangement thus assures that the core barrel and its cutter head may be readily removed whenever desired after the coring operation is complete. As has been noted, the particular details of construction of the bit form no part of the present invention and the same may be applied to any standard type of core bit now on the open market and usable with removable core taking equipment.

Although it is desirable that the upper portion of opening I5 be tapered or gradually enlarged, it is pointed out that this upper portion could be of a constant diameter which would be larger than the diameter of the section 20. This would make the space-A an annular enlarged space about the core barrel rather than tapered as shown. It would also be possible to form the opening of the same diameter throughout its entire length, which diameter would be substantially equal to the external diameter of the cutter head; in such casethe longitudinal grooves or recesses 22 would extend throughout the length of the bore of the opening to provide circulation past the core head.

The foregoin disclosure and description of the invention is illustrative and explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within the scope of the appended claims, without departing from the spirit of the invention.

Having described the invention, I claim:

1. The combination with a removable core barrel of a drill bit having a transverse bridge member for supporting the cutters of the bit with a space above said bridge member in which formation cuttings from the cutters may accumulate, said bridge member having an axial opening therein through which the removable core barrel is adapted to extend and the upper portion of said opening being enlarged in diameter, whereby said core barrel may be removed from the bit even though cuttings may accumulate in said axial opening exteriorly of said core barrel.

2. The combination with a removable core barrel of a drill bit having a transverse bridge memher for supportin the cutters of the bit with a space above said bridge'member in which formation cuttings from the cutters may accumulate, said bridge member having an axial opening therein through which the removable core barrel is adapted to extend, said opening having its lower portion of a constant diameter and having its upper portion gradually tapered outwardly from said constant diameter portion to the upper end thereof, whereby said core barrel may be removed from the bit even though cuttings may accumulate in said axial opening exteriorly of said core barrel.

3. Ina rotary drilling bit having therewith a removable core barrel, a bit body, cutters mounted on said body, a transverse bridge member disposed between the cutters for supporting same in conjunction with said cit body, said bridge member and said cutters having a space thereabove in which cuttings, slush and the like may accumulate, said bridge member having an axial opening through which the core barrel is adapted to extend, and the upper portion of said opening being enlarged in'diameter, whereby said core barrel may be removed from the bit even tho'ughcuttings may accumulate in said axial opening exteriorly of said core barrel.

4. The drilling bit as set forth in claim 3, wherein said bit body has an axial bore with a portion for vertically aligning the core barrel, said portion being spaced above said bridge member.

5. The drilling bit as set forth in claim 3, wherein said bit body has slush passages therein with the discharge ends thereof disposed above said space, whereby the slush is supplied into said space above said cutters and said bridge member.

6. The structure set forth in claim 2, including longitudinal circulation grooves radially spaced in the wall of said axial opening ofsaid bridge member to allow circulation past the core barrel when it is in said opening.

JOHN C. STOKES.

References Cited in the file of this patent 

